I had the same error. Do composer update and make sure your app directory is up to date with the latest changes in the upstream Laravel git repository

I have newest files and problem is still there. Any other sugestions?

For me the error was that I should use namespaces for the controllers in the helpers. The following gives me the weird error (Call to a member function domain() on a non-object).

action("HomeController@showWelcome") 

Where by adding the namespace it started working. The error is not really helpful.

action("App\Http\Controllers\HomeController@showWelcome")

With the newly released version of Laravel 5, I experienced the exact opposite.

return redirect()->action('App\Http\Controllers\HomeController@index');

caused the domain() on null, where as the following:

return redirect()->action('HomeController@index');

worked fine. Quite misleading as the documentation specifies using the first approach... O_o

Update: So - it seems action() returns the url routing to this particular method. I was attempting to use it without an existing route to a method which works with neither of the approaches above. For good reason I guess. In my case I should probably just call the function specifically rather than using the routing system as a way to control my program flow.

In any case, my previous statement stands. Of the two methods, the latter works for me IF you've already defined a route for that particular method. Otherwise, both methods will return the null domain function thingy ka-jigger.

I had the same issue when misspelling my controller name in action().

Example:

action('UserController@update', $user->id) // causes the error.
action('UsersController@update', $user->id) // It should be this. (notice the s in Users)